How do I understand the 3 lines batch script?

Question

ECHO @ECHO OFF ^& (IF EXIST "%%~dp0%~n1.swf" (DEL "%%~dp0%~n1.swf")) ^& %mxmlcPath% %opts% -file-specs "%%~dp0%~nx1" ^& (IF EXIST "%%~dp0%~n1.swf" (CALL "%%~dp0%~n1.swf") ELSE (PAUSE)) > "%~dpn1.bat"
REM Immediately execute the generated bat
@ECHO on
CALL "%~dpn1.bat"

It's really a mess for me(like ECHO @ECHO OFF,what's that intended for?), can someone elaborate it?

Answer 1

First line generates the batch file (note the '>' redirecting the output to the file at the end of first line). Third line ensures the output will be visible, fourth line executes the batch file generated in first line.

As for what the generated batch do: it seems it recreates some swf file: first the swf file is deleted:

"(IF EXIST "%%~dp0%~n1.swf" (DEL "%%~dp0%~n1.swf"))" 

then it is created using program defined in mxmlcPath environment variable:

%mxmlcPath% %opts% -file-specs "%%~dp0%~nx1"

if it's created successfully, it runs it in default swf player:

(IF EXIST "%%~dp0%~n1.swf" (CALL "%%~dp0%~n1.swf")

in other cases it waits for user input (so you will be able to read all error messages, etc.):

ELSE (PAUSE)

Explanation of the syntax of all the "%~dp0", etc. is available in documentation of few windows commands, for example:

call /?